466 Bibliog raphical Notice. 



not been done by others before him, liut a word of caution seems 

 to be needed. We have no doubt that the authors to whom he is 

 so largely indebted are animated by no niggard spirit, and will 

 rejoice that a larger number may participate in the fruit of their 

 labours, ^ye may hope, too, that of those who may be allured by 

 Mr. Pennington's work to the study of natural history, not a few 

 will be led on to the original sources from which he has drawn. 

 None the less, however, is it right that the line should be clearly 

 drawn between the two very distinct kinds of compilation — that 

 which is an exposition of the work of others, informed and vivified 

 by the spirit of the compiler and adapted by him to his special pur- 

 pose, and that which is in great measure mere wholesale appropria- 

 tion. The latter, unless it be with the concurrence of the author 

 whose interests are involved, cannot be accounted legitimate. 



With this caveat it may be admitted that Mr. Pennington's 

 manual may prove a useful guide to those who desire to collect 

 and study the British species of Coelenterata and Polyzoa. but are 

 unable to command the large and necessarily costly books to which 

 we have referred. At the same time its value to the student, so 

 far as the Polyzoa are concerned, is considerably reduced by the very 

 imperfect diagnosis given of many of the species. Indeed in a large 

 number of cases there is nothing worthy of the name of a diagnosis, 

 a few particulars loosely and vaguely stated, or a fancied resemblance 

 to some familar object, doing duty for the minute and precise account 

 of the morphological characters which (in this class especially) is 

 essential to sure identification. This may give a more "popular" 

 character to the book, but it must necessarily affect both its scien- 

 tific value and its practical utility. A great change has passed over 

 the systematic treatment of the Polyzoa within very recent times, 

 and the meagre and indefinite descriptions which the earlier natu- 

 ralists have left us (with a few illustrious exceptions), and which 

 were still general till within the last few years, are no longer ac- 

 cepted as sufficient. The evolutionary movement has rendered new 

 methods necessary, and as a result we have now much greater pre- 

 cision and fulness ia diagnosis, and consequently much more certain 

 identification and much surer data for the study of varietal forms. 

 We should regret to see a return to the old ways even in ele- 

 mentary works. It is only fair to add that, to a large extent, Mr. 

 Pennington must have been hampered by the conditions under 

 which his manual has been prepared. It would have been diffi- 

 cult to do full justice to his subject within the limits prescribed for 

 him. 



Objection may fairly be taken to the title of the work, on the 

 grouad that it is likely to perpetuate a false idea of the relationship 

 existing between the tribes embraced under it ; these, though in 

 part referable to distinct divisions of the animal kingdom and 

 widely different in structure, are blended in a single groujj under a 

 common name. We cannot admit the force of Mr. Pennington's 

 plea for the course which he has adopted. The fact that some of the 

 Polyzoa " are as much plant -like in appearance as the Hydroids '' 



